The US government is in possession of 250,000 pages of documents relating to the transmission of state secrets to whistleblower website WikiLeaks, which it is refusing to disclose to defence lawyers representing the alleged source of the leaks, Bradley Manning.

Manning's civilian lawyer, David Coombs, has lodged a motion with the military court that is hearing the court-martial of the US soldier. Coombs writes in the motion that the government has revealed to him in a throwaway footnote that there are 250,000 pages in its possession that relate to Manning, WikiLeaks and secret official assessments of the damage that the massive leak caused to US interests around the world.

Yet none of these pages have been made available to the defence. "If so, this is very disconcerting to the defence," Coombs says.

Manning, an intelligence analyst who was working outside Baghdad when he was arrested two years ago, is charged with 22 counts connected to the largest leak of state secrets in US history.

In the motion, published in redacted form on his website, Coombs renews his long-standing efforts to compel the US government to hand over information that could prove crucial in preparing Manning's defence.

He accuses the army of continuing to resist its legal obligations to disclose anything that could help Manning prove his innocence or achieve a lighter sentence.

The motion is one of several defence motions that have been submitted to the court and that will be the subject of a pre-trial hearing at Fort Meade in Maryland. Manning himself is likely to attend the hearing, which comes three months before a full trial, which is scheduled for 21 September.

The language of Coombs's legal submission suggests that the lawyer, who himself has a military background, is growing increasingly frustrated by the obfuscations and alleged sleights of hand played by the prosecution.